Magazine allows the same cartridge length as an AR magazine...
The twist will handle anything you feed it under 80 grains ( and including 80 grains).. it is just you have to seat the bullets very very deep into the case...
75BTHPs are a little more user friendly in that aspect, than the 75 A Maxes... I have shot the 80 grain A Maxes and various 80 grain Match bullets out of mine, with fine results...
Its a pain, but I have been single feeding them seated out as far as the throat will take them, which is longer than the magazine for sure...
Mine is the Predator Model, so I don't know if there is a difference with it and the standard Model American....
our forum member Cotis has a thread going where he is making an extension to the factory mag, which will handle the longer bullets seated further out... that and having the throat reamed out a hair should turn the American into a much more desirable and capable rifle...offering a lot more versatility...
